Venturi vacuum drawback assemblies and dual orifice venturi valve assemblies

ABSTRACT

A venturi vacuum drawback assembly includes a fluid supply passage that supplies the fluid to the device, a fluid return passage that returns the fluid to the device, a shutoff valve positioned on the fluid supply passage, a bypass passage, a bypass valve positioned on the bypass passage, and a venturi valve positioned on the bypass passage downstream of the bypass valve. The bypass passage includes an inlet and an outlet. The inlet is connected to the fluid supply passage upstream of the shutoff valve, and the outlet connected to the fluid return passage. The venturi valve includes a venturi inlet, a venturi outlet, and a primary orifice positioned between the venturi inlet and the venturi outlet. The primary orifice is connected to a drawback opening on the fluid supply passage by a conduit. The drawback opening of the fluid supply passage is positioned downstream of the shutoff valve.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/828,298 filed Nov. 30, 2017 which claims priority to U.S. ProvisionalPatent Application Ser. No. 62/428,089 filed Nov. 30, 2016 both of whichare incorporated herein by reference.

TECHNICAL FIELD

The present disclosure is directed to a venturi vacuum drawbackassemblies for controlling the flow of a fluid, more particularly,venturi vacuum drawback assemblies that include a bypass passage thatcreates a drawback vacuum using a venturi valve.

BACKGROUND

Previously known coolant delivery systems include a coolant supplypassage and a coolant return passage. The coolant supply passage runsfrom a supply of coolant to a device to be cooled. The coolant returnpassage runs from the device to be cooled to a coolant recirculatingdevice. The coolant recirculating device removes the heat added to thecoolant by the device to be cooled and then recirculates the coolant tothe coolant supply.

In addition, the previously known coolant delivery systems areconfigured to close the coolant supply passage upon the detection of aleak. However, any coolant that remains in the coolant supply passagedownstream from the closure will continue to discharge from the leak.The continuous discharge of coolant even after the closure of thecoolant supply passage increases the stop work delay due to repair ofthe leak and clean the discharged coolant.

Accordingly, a need exists for alternative systems and methods fordraining coolant that remains in a coolant delivery system downstreamfrom a closure after leak detection.

SUMMARY

In one embodiment, a venturi vacuum drawback assemblies for controllinga flow of a fluid from a device includes a fluid supply passage, a fluidreturn passage, a shutoff valve, a bypass passage, a bypass valve, and aventuri valve. The fluid supply passage supplies the fluid to thedevice. The fluid return passage returns the fluid from the device. Theshutoff valve is positioned on the fluid supply passage. The bypasspassage includes an inlet and an outlet. The inlet is connected to thefluid supply passage upstream of the shutoff valve, and the outlet isconnected to the fluid return passage. The bypass valve is positioned onthe bypass passage. The venturi valve is positioned on the bypasspassage upstream of the bypass valve. The venturi valve includes aventuri inlet, a venturi outlet, and a primary orifice positionedbetween the venturi inlet and the venturi outlet. The primary orifice isconnected to a drawback opening on the fluid supply passage by aconduit. The drawback opening of the fluid supply passage is positioneddownstream of the shutoff valve.

In another embodiment, a venturi vacuum drawback assemblies forcontrolling a flow of a fluid from a device includes a primary fluidsupply passage, a primary fluid return passage, a primary shutoff valve,a secondary fluid supply passage, a secondary fluid return passage, asecondary shutoff valve, a bypass passage, a bypass valve, and a venturivalve. The primary fluid supply passage supplies the fluid to thedevice. The primary fluid return passage returns the fluid from thedevice. The primary shutoff valve is positioned on the primary fluidsupply passage. The secondary fluid supply passage supplies the fluid tothe device. The secondary fluid return passage returns the fluid fromthe device. The secondary shutoff valve is positioned on the secondaryfluid supply passage. The bypass passage includes an inlet and anoutlet. The inlet connected to the primary fluid supply passage upstreamof the primary shutoff valve, and the outlet is connected to the primaryfluid return passage. The bypass valve is positioned on the bypasspassage. The venturi valve is positioned on the bypass passage upstreamof the bypass valve. The venturi valve includes a venturi inlet, aventuri outlet, a primary orifice, and a secondary orifice. The primaryorifice is positioned between the venturi inlet and the venturi outlet.The secondary orifice is positioned between the venturi inlet and theventuri outlet. The primary orifice is connected to a primary drawbackopening on the primary fluid supply passage by a primary conduit. Theprimary drawback opening of the primary fluid supply passage ispositioned downstream of the primary shutoff valve. The secondaryorifice is connected to a secondary drawback opening on the secondaryfluid supply passage by a secondary conduit. The secondary drawbackopening of the secondary fluid supply passage is positioned downstreamof the secondary shutoff valve.

In another embodiment, a dual orifice venturi valve assembly includes aventuri valve that includes a venturi inlet, a venturi outlet, a firstconstricted portion, and a second constricted portion. The firstconstricted portion and the second constricted portion are positionedbetween the venturi inlet and the venturi outlet. The first constrictedportion includes a primary orifice and a secondary orifice. The firstconstricted portion includes an inlet orifice having an inlet diameterat a junction between the first constricted portion and the secondconstricted portion. The first constricted portion includes an outletorifice having an outlet diameter greater than the inlet diameter. Anarea of the outlet orifice is equal to or less than a sum of an area ofthe inlet orifice, an area of the primary orifice, and an area of thesecondary orifice diameter.

These and additional features provided by the embodiments describedherein will be fully understood in view of the following detaileddescription, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplaryin nature and not intended to limit the subject matter defined by theclaims. The following detailed description of the illustrativeembodiments can be understood when read in conjunction with thefollowing drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1 schematically depicts a venturi vacuum drawback assembly forcontrolling a flow of a fluid from a device, according to one or moreembodiments shown and described herein;

FIG. 2 schematically depicts a partial cross-sectional view of a venturivalve of the venturi vacuum drawback assemblies of FIG. 1, according toone or more embodiments shown and described herein;

FIG. 3 schematically depicts a venturi vacuum drawback assembly forcontrolling the flow of the fluid from the device, according to one ormore embodiments shown and described herein;

FIG. 4A schematically depicts a partial side view of a venturi valve ofthe venturi vacuum drawback assembly of FIG. 3, according to one or moreembodiments shown and described herein

FIG. 4B schematically depicts a partial cross-sectional view of theventuri valve of the venturi vacuum drawback assembly taken along thelines B-B of FIG. 4A, according to one or more embodiments shown anddescribed herein;

FIG. 4C schematically depicts a partial cross-sectional view of aventuri valve of the venturi vacuum drawback assembly taken along thelines C-C of FIG. 4B, according to one or more embodiments shown anddescribed herein; and

FIG. 5 schematically depicts a venturi vacuum drawback assembly forcontrolling a flow of a fluid from a device, according to one or moreembodiments shown and described herein.

DETAILED DESCRIPTION

Venturi vacuum drawback assemblies of the present disclosure include afluid supply passage, a fluid return passage, a shutoff valve, a bypasspassage, a bypass valve, and a venturi valve. The fluid supply passagesupplies the fluid to a device. The fluid return passage returns thefluid from the device. The shutoff valve is positioned on the fluidsupply passage. The bypass passage includes an inlet and an outlet. Theinlet is connected to the fluid supply passage upstream of the shutoffvalve, and the outlet connected to the fluid return passage. The bypassvalve is positioned on the bypass passage. The venturi valve ispositioned on the bypass passage upstream of the bypass valve. Theventuri valve includes a venturi inlet, a venturi outlet, and a primaryorifice positioned between the venturi inlet and the venturi outlet. Theprimary orifice is connected to a drawback opening on the fluid supplypassage by a conduit. The drawback opening of the fluid supply passageis positioned downstream of the shutoff valve.

Upon movement of the shutoff valve from a normally open position to aclosed position and movement of the bypass valve from a normally closedpositon to an open position, fluid is inhibited from flowing through theshutoff valve to the device and fluid is permitted to flow through thebypass passage including the venturi valve. The flow of fluid throughthe venturi valve creates a vacuum at the primary orifice which drawsback fluid contained in the fluid supply passage downstream of theshutoff valve. The fluid in the fluid supply passage downstream of theshutoff valve is drawn through the conduit into the venturi valve of thebypass passage so as to exit the bypass passage and into the fluidreturn passage.

FIG. 1 generally depicts a coolant delivery system 1 to which a venturivacuum drawback assembly 10 is applied. The coolant delivery system 1includes a device 12 to be cooled by a fluid, for example a coolant. Inthe illustrated embodiment, the device 12 includes a device inlet 14, adevice outlet 16, and a cooling part 18. Fluid flows into the deviceinlet 14 to cool the cooling part 18 and the fluid, heated by thecooling part 18, exits through the device outlet 16. In someembodiments, the cooling part 18 includes a pair of cooling parts 18A.In the illustrated embodiment, the device 12 is a robotic welding deviceand the cooling parts 18A are a pair of weld tips 18A of the roboticwelding device.

Referring to FIG. 1, the venturi vacuum drawback assembly 10 includes afluid supply 30, a fluid supply passage 22, a fluid return 34, and afluid return passage 24. The device inlet 14 is connected to a fluidsupply 30 by the fluid supply passage 22. The device outlet 16 isconnected to the fluid return 34 by the fluid return passage 24. In someembodiments, the fluid return 34 includes a coolant recirculating device(not shown). The coolant recirculating device, such as refrigerator,removes the heat added to the coolant by the device 12 to be cooled, andthen recirculates the coolant to the fluid supply 30.

The venturi vacuum drawback assembly 10 may also include a flowmeterunit 20 that is provided on at least one of the fluid supply passage 22and the fluid return passage 24. The flowmeter unit 20 includes a supplyoutlet 21 and a supply inlet 26 on the fluid supply passage 22. Thesupply outlet 21 connects to the device inlet 14 of the device 12 by thefluid supply passage 22 downstream of the flowmeter unit 20. The supplyinlet 26 connects to the fluid supply 30 upstream of the flowmeter unit20. The flowmeter unit 20 includes a return inlet 25 and a return outlet32 on the fluid return passage 24. The return inlet 25 connects to thedevice outlet 16 of the device 12 through the fluid return passage 24upstream of the flowmeter unit 20. The return outlet 32 connects to thefluid return 34 through the fluid return passage 24 downstream of theflowmeter unit 20. As described in greater detail below, the flowmeterunit 20 detects leaks from cap loss, hose burst, or inadvertent shutoffand outputs a leak signal upon the detection of a leak.

The venturi vacuum drawback assembly 10 may also include a shutoff valve28 that is positioned on the fluid supply passage 22 upstream of theflowmeter unit 20. Specifically, the shutoff valve 28 is provided on thefluid supply passage 22 upstream of the supply inlet 26. The shutoffvalve 28 is switchable between a normally open position and a closedposition. In the open position, the shutoff valve 28 allows coolant fromthe fluid supply 30 to flow into the supply inlet 26. In the closedposition, the shutoff valve 28 inhibits fluid flowing from the fluidsupply 30 through the shutoff valve 28 to the supply inlet 26.

The venturi vacuum drawback assembly 10 also includes a bypass passage36, a bypass valve 42, a venturi valve 44, and a conduit 46 thatconnects the venturi valve 44 to the fluid supply passage 22 downstreamof the shutoff valve 28. The bypass passage 36 includes a bypass inlet38 and a bypass outlet 40. The bypass inlet 38 is positioned on thefluid supply passage 22 upstream of the shutoff valve 28. The bypassoutlet 40 is positioned on the fluid return passage 24 downstream of thereturn outlet 32.

The bypass valve 42 is switchable between a normally closed position andan open position. In the closed position, the bypass valve 42 inhibitsfluid from passing through the bypass passage 36. In the open position,the bypass valve 42 allows fluid to flow through the bypass passage 36to bypass the device 12. Specifically, the fluid that flows through thebypass passage 36 bypasses the supply inlet 26, the flowmeter unit 20,the supply outlet 21, the device inlet 14, the device 12, the coolingpart 18, the device outlet 16, the return inlet 25, the flowmeter unit20, and the return outlet 32 so as to enter the fluid return passage 24.

The venturi valve 44 is positioned on the bypass passage 36 between thebypass inlet 38 and the bypass valve 42. The venturi valve 44 includes aventuri inlet 48, a venturi outlet 50, and a primary orifice 52positioned between the venturi inlet 48 and the venturi outlet 50.

A drawback opening 54A is provided on the fluid supply passage 22downstream of the flowmeter unit 20. Specifically, the drawback opening54A is positioned on the fluid supply passage 22 between the supplyoutlet 21 and the device inlet 14. The conduit 46 connects the primaryorifice 52 to the drawback opening 54A In some embodiments, a checkvalve 45 is positioned between the drawback opening 54A and the primaryorifice 52 of the venturi valve 44.

In some embodiments, a drawback opening 54B is provided on the fluidreturn passage 24 upstream of the flowmeter unit 20. Specifically, thedrawback opening 54B is positioned on the fluid return passage 24between the return inlet 25 and the device outlet 16. In someembodiments, the conduit 46 includes a junction 55 that splits theconduit 46 to connect the primary orifice 52 to at least one of thedrawback opening 54A and the drawback opening 54B. The junction 55splits the conduit 46 to connect the primary orifice 52 to both thedrawback opening 54A and the drawback opening 54B. A check valve 45 ispositioned between the junction 55 and the primary orifice 52 of theventuri valve 44 so as to prevent fluid from flowing from the primaryorifice 52 of the venturi valve 44 to the drawback opening 54A and 54B.In some other embodiments, the check valve 45 is positioned between thejunction 55 and the drawback opening 54A and a check valve 45 ispositioned between the junction 55 and the drawback opening 54B.

Referring to FIG. 2, the venturi valve 44 includes a first constrictedportion 60A and a second constricted portion 60B. The first constrictedportion 60A includes an inlet orifice 62 and an outlet orifice 64. Theprimary orifice 52 is positioned at the first constricted portion 60Abetween the inlet orifice 62 and the outlet orifice 64. As such, theinlet orifice 62 is the opening of the first constricted portion 60Athat is in communication with the second constricted portion 60B. Thesecond constricted portion 60B is in communication with the venturiinlet 48. The outlet orifice 64 is the opening of the first constrictedportion 60A that is in communication with the venturi outlet 50.

In some embodiments, the venturi valve 44 includes an inlet passage 62Aand an outlet passage 64A. The inlet passage 62A extends between secondconstricted portion 60B and the venturi inlet 48. The outlet passage 64Aextends between the outlet orifice 64 and the venturi outlet 50.

The primary orifice 52 includes a diameter Dl at the first constrictedportion 60A. The inlet orifice 62 includes a diameter D2 at the junctionbetween the first constricted portion 60A and the second constrictedportion 60B. The outlet orifice 64 includes a diameter D3 at the firstconstricted portion 60A. The inlet orifice 62 is the junction of thefirst constricted portion 60A and the second constricted portion 60Bwhere the diameter D2 changes from to the diameter D3. In someembodiments, the first constricted portion 60A includes the diameter D3and the second constricted portion 60B includes the diameter D2.

In some embodiments, the diameter D3 of the outlet orifice 64, thediameter Dl of the primary orifice 52, and the diameter D2 of the inletorifice 62 are dimensioned such that an area of outlet orifice 64 isequal to a sum of an area of the primary orifice 52 and an area of theinlet orifice 62. As such, a velocity of the fluid flowing through theinlet orifice 62 is substantially equal to a velocity of the fluidflowing through the primary orifice 52 which is substantially equal to avelocity of the fluid flowing through the outlet orifice 64.

In some other embodiments, the diameter D3 of the outlet orifice 64, thediameter Dl of the primary orifice 52, and the diameter D2 of the inletorifice 62 are dimensioned such that the area of outlet orifice 64 isless than the sum of the area of the primary orifice 52 and the area ofthe inlet orifice 62. For example, the area of the outlet orifice 64 isless than the sum of the area of the primary orifice 52 and the area ofthe inlet orifice 62 by at least 0.1%, such as at least 1%, such as atleast 5%, such as at least 10%.

In some embodiments, the first constricted portion 60A is generallycylindrically shaped having the diameter D3, and the second constrictedportion 60B is generally cylindrical shaped having the diameter D2. Assuch, the inlet orifice 62 at the junction of the first constrictedportion 60A and the second constricted portion 60B has the diameter D2and the outlet orifice 64 has the diameter D3 that is less than theinlet diameter D2.

In some embodiments, the first constricted portion 60A and the secondconstricted portion 60B constrict the diameter of the venturi valve 44so as to reduce a pressure as the fluid flows through the secondconstricted portion 60B and then the first constricted portion 60A whichcreates a vacuum at the primary orifice 52 located in the firstconstricted portion. In some embodiments, the first constricted portion60A and the second constricted portion 60B are dimensioned such that anarea of the outlet orifice 64 is equal to or less than a sum of an areaof the inlet orifice 62 and an area of the primary orifice 52.

Referring to FIG. 1, the flowmeter unit 20 is configured to detectdifferences in flow between the fluid flowing through the fluid supplypassage 22 and the fluid return passage 24. Specifically, a supplyflowmeter 20A is provided between the supply outlet 21 and a supplyinlet 26 and a return flowmeter 20B is provided between the return inlet25 and the return outlet 32. The flowmeter unit includes an electroniccontrol unit 70.

Examples of a flowmeter unit 20 that may be used in the disclosedventuri vacuum drawback assembly 110 include, but are not limited to,the Delta Point®, Ethernet Delta Point®, 24V DC Delta Point®, 120V ACDelta Point®, and DeviceNet Delta Point®, sold by Rocon LLC of HazelPark, Mich. It will be appreciated, of course, that other flowmeterunits may also be used in conjunction with the venturi vacuum drawbackassembly 10.

The electronic control unit 70 is electronically connected to theshutoff valve 28 and the bypass valve 42. Specifically, the electroniccontrol unit 70 is configured to control the operation of the shutoffvalve 28 between the normally open position and the closed position. Theelectronic control unit 70 is further configured to control theoperation of the bypass valve 42 between the normally closed positionand the open position. In some embodiments, the shutoff valve 28 and thebypass valve 42 are electronically controlled solenoid valves that arecontrolled by the electronic control unit 70.

In some embodiments, the electronic control unit 70 includes a processor72 and a memory component 74 coupled to the processor 72. The processor72 is a central processing unit (CPU). The processor 72 includesprocessing components operable to receive and execute instructions fromthe memory component 74. The memory component 74 stores detection logic74A and control logic 74B. The detection logic 74A and the control logic74B may each include a plurality of different pieces of logic, each ofwhich may be embodied as a computer program, firmware, and/orsoftware/hardware.

In some embodiments, the memory component 74 is configured as volatileand/or nonvolatile memory and as such may include random access memory(SRAM, DRAM, and/or other types of RAM), flash memory, secure digital(SD) memory, registers, compact discs, digital versatile discs (DVD),and/or other types of nontransitory computer readable mediums. Dependingon the particular embodiments, these nontransitory computer readablemediums may reside within the electronic control unit 70 and/or externalto the electronic control unit 70 and the flowmeter unit 20.

The detection logic 74A is executable by the processor 72 to detect oneor more signals output from the supply flowmeter 20A and the returnflowmeter 20B. For example, the detection logic 74A is configured tocause the processor 72 to determine a presence or absence of a leak inthe coolant delivery system 1, specifically, a leak in at least one ofthe fluid supply passage 22, the device 12, including device inlet 14and the device outlet 16, and the fluid return passage 24 based on thesignals output from at least one of the supply flowmeter 20A and thereturn flowmeter 20B. Specifically, processor 72 determines the presenceor absence of the leak based on output signals from the supply flowmeter20A and the return flowmeter 20B that indicate the flowrates of thefluid supply passage 22 and the fluid return passage 24, respectively.

The control logic 74B is executed by the processor 72 to controloperation of the shutoff valve 28 and the bypass valve 42 based on thedetermination of the presence or absence of a leak in the coolantdelivery system 1 by the processor 72. In some embodiments, when theprocessor 72 has determined the absence of a leak, the control logic 74Bis executed by the processor 72 to control the shutoff valve 28 into thenormally open position and the control logic 74B controls the bypassvalve 42 in the normally closed position.

In order to facilitate a better understanding of the venturi vacuumdrawback assembly 10, a discussion of the operation of the venturivacuum drawback assembly 110 will be provided. During operation in whichthe processor 72 determines the absence of a leak, the coolant deliverysystem 1 operates to deliver fluid from the fluid supply 30 to thedevice 12 through the fluid supply passage 22 and returns the fluid fromthe device 12 through the fluid return passage 24 to the recirculationdevice connected to the fluid return 34. Specifically, during suchoperation, the shutoff valve 28 is in the normally open position and thebypass valve 42 is in the normally closed position. As fluid flowsthrough the fluid supply passage 22, the fluid is prevented from flowingthrough the bypass passage 36 as the bypass valve 42 is in the normallyclosed position.

During operation in which the processor 72 determines the presence of aleak, the venturi vacuum drawback assembly 10 operates to control theflow of fluid from the device 12. Specifically, upon the processor 72determining the presence of a leak based on the one or more signalsoutput from the supply flowmeter 20A and the return flowmeter 20B anddetected by the detection logic 74A, the control logic 74B is executedby the processor 72 to control the shutoff valve 28 from the normallyopen position to the closed position and to control the bypass valve 42from the normally closed position to the open position.

In some embodiments, the processor 72 executes the control logic 74B toswitch the bypass valve 42 from the normally closed position to the openposition simultaneously with the switching of the shutoff valve 28 fromthe normally open position to the closed position. In some embodiments,the processor 72 executes the control logic 74B to switch the bypassvalve 42 from the normally closed position to the open position after anelapse of a preset time period after switching of the shutoff valve 28from the normally open position to the closed position.

In the closed position, the shutoff valve 28 prevents fluid from flowingfrom the fluid supply 30 through the shutoff valve 28 to the device 12.As fluid is prevented from flowing in the fluid supply passage 22,downstream of the shutoff valve 28, additional fluid is prevented frombeing discharged through the leak. As the bypass valve 42 is in the openposition, fluid is permitted to flow through the bypass passage 36 fromthe bypass inlet 38 on the fluid supply passage 22 upstream of theshutoff valve 28 to the bypass outlet 40 on the fluid return passage 24downstream of the return outlet 32.

As such, fluid flows through the bypass passage 36 including the venturivalve 44. Due to the venturi effect of the venturi valve 44, a pressurein the venturi valve 44 upstream of the primary orifice 52 is higherthan the pressure downstream of the primary orifice 52 due to the changein cross-sectional area at the first constricted portion 60A and thesecond constricted portion 60B. Accordingly, the fluid remaining in thefluid supply passage 22 downstream of the shutoff valve 28 is at ahigher pressure than the pressure at the primary orifice 52 and thefluid moves from the area of high pressure to the area of low pressureto drain the fluid that remains in the fluid supply passage 22 throughthe venturi valve 44 so as to exit through the fluid return passage 24.Similarly, the fluid remaining in the fluid return passage 24 upstreamof the flowmeter is at a higher pressure than the pressure at theprimary orifice 52 and the fluid moves from the area of high pressure tothe area of low pressure to drain the fluid that remains in the fluidreturn passage 24 through the venturi valve 44 so as to exit through thefluid return passage 24.

As such, the decrease in pressure creates a vacuum at the primaryorifice 52 allowing the fluid that remains in the fluid supply passage22 downstream of the shutoff valve 28 to be drawn through drawbackopening 54A and into the primary orifice 52 via the conduit 46. Fluiddrawn through the primary orifice 52 exits the venturi valve 44 via theventuri outlet 50 and enters the fluid return passage 24 via the bypassoutlet 40. Therefore, the remaining fluid in the fluid supply passage 22downstream of the shutoff valve 28 will not discharge through the leakdue to the vacuum effect of the venturi valve 44.

Similarly, the decrease in pressure creates a vacuum at the primaryorifice 52 allowing the fluid that remains in the fluid return passage24 downstream of the device 12 to be drawn through drawback opening 54Band into the primary orifice 52 via the conduit 46. Fluid drawn throughthe primary orifice 52 exits the venturi valve 44 via the venturi outlet50 and enters the fluid return passage 24 via the bypass outlet 40.Therefore, the remaining fluid in the fluid return passage 24 downstreamof the device 12 will not discharge through the leak due to the vacuumeffect of the venturi valve 44.

In some embodiments, the venturi valve 44 not only draws back the fluidin the fluid supply passage 22 that is upstream and/or downstream of theleak and draws back the fluid in the fluid return passage 24 that isupstream and/or downstream of the leak.

Referring to FIG. 3, a venturi vacuum drawback assembly is generallyillustrated at 10′. The venturi vacuum drawback assembly 10′ is similarto the venturi vacuum drawback assembly 10 except that the venturivacuum drawback assembly 10 includes a dual orifice venturi valve 144, asupply conduit 46A and a return conduit 46B.

The dual orifice venturi valve 144 is positioned on the bypass passage36 between the bypass inlet 38 and the bypass valve 42. The dual orificeventuri valve 144 includes a venturi inlet 148, a venturi outlet 150, aprimary orifice 152A, and a secondary orifice 152B. The primary orifice152A and the secondary orifice 152B are positioned between the venturiinlet 148 and the venturi outlet 150. The primary orifice 152A isconnected to the drawback opening 54A by the supply conduit 46A and thesecondary orifice 152B is connected to the drawback opening 54B by thereturn conduit 46B. In some embodiments, a check valve 45 is positionedon the supply conduit 46A between the primary orifice 152A and thedrawback opening 54A and a check valve 45 is positioned on the returnconduit 46B between the secondary orifice 152B and the drawback opening54B.

Referring to FIGS. 4A, 4B, and 4C, the dual orifice venturi valve 144includes a first constricted portion 160A and a second constrictedportion 160B. The first constricted portion 160A includes an inletorifice 162 and an outlet orifice 164. The primary orifice 152A and thesecondary orifice 152B are positioned at the first constricted portion160A between the inlet orifice 162 and the outlet orifice 164. The inletorifice 162 is the junction of the first constricted portion 160A andthe second constricted portion 60B. As such, the inlet orifice 162 isthe opening of the first constricted portion 160A that is incommunication with the second constricted portion 160B. The secondconstricted portion 60B is in communication with the venturi inlet 148.The outlet orifice 164 is the opening of the first constricted portion160A that is in communication with the venturi outlet 150.

In some embodiments, the dual orifice venturi valve 144 includes aninlet passage 162A and an outlet passage 164A. The inlet passage 162Aextends between the second constricted portion 160B and the venturiinlet 148. The outlet passage 164A extends between the outlet orifice164 and the venturi outlet 150.

Referring to FIG. 4B, the primary orifice 152A includes a diameter D1′at the first constricted portion 160A. Referring to FIG. 4C, thesecondary orifice 152B includes a diameter D4′ at the first constrictedportion 160A. Referring to FIGS. 4B, and 4C, the inlet orifice 162includes a diameter D2′ at the first constricted portion 160A. Theoutlet orifice 164 includes a diameter D3′ that is greater than theinlet diameter D2′. As such, the inlet orifice 162 is the junction ofthe first constricted portion 160A and the second constricted portion160B where the diameter D2 changes from to the diameter D3. The inletorifice 162 is the opening of the first constricted portion 160A that isin communication with the second constricted portion 160B. The secondconstricted portion 160B is in communication with the venturi inlet 148.The outlet orifice 164 is the opening of the first constricted portion160A that is in communication with the venturi outlet 150.

In some embodiments, the dual orifice venturi valve 144 includes aninlet passage 162A and an outlet passage 164A. The inlet passage 162Aextends between second constricted portion 160B and the venturi inlet148. The outlet passage 164A extends between the outlet orifice 164 andthe venturi outlet 150.

In some embodiments, the diameter D3′ of the outlet orifice 164, thediameter D1′ of the primary orifice 152A, the diameter D4′ of thesecondary orifice 152B, and the diameter D2′ of the inlet orifice 62 aredimensioned such that an area of outlet orifice 164 is equal to a sum ofan area of the primary orifice 152A, the secondary orifice 152B, and anarea of the inlet orifice 162.

In some embodiments, the diameter D3′ of the outlet orifice 164, thediameter D1′ of the primary orifice 152A, the diameter D4′ of thesecondary orifice 152B, and the diameter D2′ of the inlet orifice 62 aredimensioned such that the area of outlet orifice 164 is less than thesum of the area of the primary orifice 152A, the secondary orifice 152B,and the area of the inlet orifice 162. For example, the area of theoutlet orifice 164 is less than the sum of the area of the primaryorifice 152A, the area of the secondary orifice 152B, and the area ofthe inlet orifice 62 by at least 0.1%, such as at least 1%, such as atleast 5%, such as at least 10%.

As such, a velocity of the fluid flowing through the inlet orifice 162is substantially equal to a velocity of the fluid flowing through theprimary orifice 152A and the velocity of the fluid flowing through thesecondary orifice 52B which is substantially equal to a velocity of thefluid flowing through the outlet orifice 164.

In some embodiments, the first constricted portion 160A is generallycylindrically shaped having the diameter D3′, and the second constrictedportion 160B is generally cylindrically shaped having the diameter D2′.As such, the inlet orifice 162, at the junction between the firstconstricted portion 160A and the second constricted portion 160B, hasthe diameter D2′ and the outlet orifice 164 has the diameter D3′.

In some embodiments, the first constricted portion 160A and the secondconstricted portion constrict the diameter of the dual orifice venturivalve 144 so as to reduce a pressure which creates a vacuum at theprimary orifice 152A and the secondary orifice 152B. In someembodiments, the first constricted portion 160A and the secondconstricted portion 160B are dimensioned such that an area of the outletorifice 164 is equal to or less than a sum of an area of the primaryorifice 152A, an area of the secondary orifice 152B, and an area of theinlet orifice 162.

Referring to FIGS. 4A, 4B, and 4C, fluid flows through the dual orificeventuri valve 144 in a flow direction A from the venturi inlet 148towards the venturi outlet 150. In some embodiments, the dual orificeventuri valve 144 is oriented such fluid flows through the primaryorifice 152A in a first direction Al and fluid flows through thesecondary orifice 152B in a second direction A2. The first direction Alis generally perpendicular to the flow direction A and the seconddirection A2 is generally perpendicular to the flow direction A. Thefirst direction Al is also generally perpendicular to the seconddirection A2.

In order to facilitate a better understanding of the venturi vacuumdrawback assembly 10′, a discussion of the operation of the venturivacuum drawback assembly 10′ will be provided. During operation in whichthe processor 72 determines the absence of a leak, the coolant deliverysystem 1 operates to deliver fluid from the fluid supply 30 to thedevice 12 through the fluid supply passage 22 and returns the fluid fromthe device 12 through the fluid return passage 24 to the recirculationdevice connected to the fluid return 34. Specifically, during suchoperation, the shutoff valve 28 is in the normally open position and thebypass valve 42 is in the normally closed position. As fluid flowsthrough the fluid supply passage 22, the fluid is prevented from flowingthrough the bypass passage 36 as the bypass valve 42 is in the normallyclosed position.

During operation in which the processor 72 determines the presence of aleak, the venturi vacuum drawback assembly 10 operates to control theflow of fluid from the device 12. Specifically, upon the processor 72determining the presence of a leak based on the one or more signalsoutput from the supply flowmeter 20A and the return flowmeter 20B anddetected by the detection logic 74A, the control logic 74B is executedby the processor 72 to control the shutoff valve 28 from the normallyopen position to the closed position and to control the bypass valve 42from the normally closed position to the open position.

In some embodiments, the processor 72 executes the control logic 74B toswitch the bypass valve 42 from the normally closed position to the openposition simultaneously with the switching of the shutoff valve 28 fromthe normally open position to the closed position. In some embodiments,the processor 72 executes the control logic 74B to switch the bypassvalve 42 from the normally closed position to the open position after anelapse of a preset time period after switching of the shutoff valve 28from the normally open position to the closed position.

In the closed position, the shutoff valve 28 prevents fluid from flowingfrom the fluid supply 30 through the shutoff valve 28 to the device 12.As fluid is prevented from flowing in the fluid supply passage 22,downstream of the shutoff valve 28, additional fluid is prevented frombeing discharged through the leak. As the bypass valve 42 is in the openposition, fluid is permitted to flow through the bypass passage 36 fromthe bypass inlet 38 on the fluid supply passage 22 upstream of theshutoff valve 28 to the bypass outlet 40 on the fluid return passage 24downstream of the return outlet 32.

As such, fluid flows through the bypass passage 36 including the dualorifice venturi valve 144. Due to the venturi effect of the dual orificeventuri valve 144, a pressure in the dual orifice venturi valve 144upstream of the primary orifice 152A and the secondary orifice 152B ishigher than the pressure downstream of the primary orifice 152A due tothe change in cross-sectional area at the first constricted portion 160Aand the second constricted portion 160B. Accordingly, the fluidremaining in the fluid supply passage 22 downstream of the shutoff valve28 is at a higher pressure than the pressure at the primary orifice 152Aand the fluid moves from the area of high pressure to the area of lowpressure to drain the fluid that remains in the fluid supply passage 22through the dual orifice venturi valve 144 so as to exit through thefluid return passage 24. Similarly, the fluid remaining in the fluidreturn passage 24 upstream of the flowmeter unit 20 is at a higherpressure than the pressure at the secondary orifice 152B and the fluidmoves from the area of high pressure to the area of low pressure todrain the fluid that remains in the fluid return passage 24 through thedual orifice venturi valve 144 so as to exit through the fluid returnpassage 24.

As such, the decrease in pressure creates a vacuum at the primaryorifice 152A allowing the fluid that remains in the fluid supply passage22 downstream of the shutoff valve 28 to be drawn through drawbackopening 54A and into the primary orifice 52 via the supply conduit 46A.Fluid drawn through the primary orifice 52 exits the dual orificeventuri valve 144 via the venturi outlet 50 and enters the fluid returnpassage 24 via the bypass outlet 40. Therefore, the remaining fluid inthe fluid supply passage 22 downstream of the shutoff valve 28 will notdischarge through the leak due to the vacuum effect of the venturi valve44.

Similarly, the decrease in pressure creates a vacuum at the secondaryorifice 152B allowing the fluid that remains in the fluid return passage24 downstream of the device 12 to be drawn through drawback opening 54Band into the secondary orifice 152B via the return conduit 46B. Fluiddrawn through the secondary orifice 152B exits the dual orifice venturivalve 144 via the venturi outlet 50 and enters the fluid return passage24 via the bypass outlet 40. Therefore, the remaining fluid in the fluidreturn passage 24 downstream of the device 12 will not discharge throughthe leak due to the vacuum effect of the venturi valve 44.

In some embodiments, the dual orifice venturi valve 144 not only drawsback the fluid in the fluid supply passage 22 that is upstream and/ordownstream of the leak and draws back the fluid in the fluid returnpassage 24 that is upstream and/or downstream of the leak.

Referring to FIG. 5, a venturi vacuum drawback assembly is generallyillustrated at 110. The venturi vacuum drawback assembly 110 is similarto the venturi vacuum drawback assembly 10′ except that the venturivacuum drawback assembly 110 includes a secondary fluid supply passage122, a secondary fluid return passage 124, a secondary flowmeter unit120, a secondary shutoff valve 128, and secondary conduit 146.

In some embodiments, the secondary fluid supply passage 122 extends fromthe fluid supply passage 22, upstream of the flowmeter unit 20, theshutoff valve 28 and the bypass inlet 38, to a secondary device inlet114 of the device 12. The secondary fluid return passage 124 extendsfrom a secondary device outlet 116 of the device 12 to the fluid returnpassage 24 downstream of the flowmeter unit 20 and bypass outlet 40. Insome embodiments, fluid is directed to one of the pair of cooling parts18A by the device inlet 14 and the device outlet 16 and fluid isdirected to the other of the pair of cooling parts 18A by the secondarydevice inlet 114 and the secondary device outlet 116.

The secondary flowmeter unit 120 includes a secondary supply outlet 121and a secondary supply inlet 126 on the secondary fluid supply passage122. The secondary supply outlet 121 connects to the secondary deviceinlet 114 of the device 12 by the secondary fluid supply passage 122downstream of the secondary flowmeter unit 120. The secondary supplyinlet 126 connects the secondary fluid supply passage 122 downstream ofthe secondary flowmeter unit 120. The secondary supply inlet 126 isconnected to the fluid supply 30 by the secondary fluid supply passage122 and the fluid supply passage 22.

The secondary flowmeter unit 120 includes a secondary return inlet 125and a secondary return outlet 132 on the secondary fluid return passage124. The secondary return inlet 125 connects to the secondary deviceoutlet 116 of the device 12 through the secondary fluid return passage124 upstream of the secondary flowmeter unit 120. The secondary returnoutlet 132 connects to the fluid return 34 through the secondary fluidreturn passage 124 downstream of the secondary flowmeter unit 120 andthe fluid return passage 24.

In some other embodiments, the secondary device inlet 114 and thesecondary device outlet 116 are provided on a secondary device 112having a secondary cooling part 118. The secondary fluid supply passage122 extends from the fluid supply passage 22, upstream of the flowmeterunit 20, the shutoff valve 28 and the bypass inlet 38, to a secondarydevice inlet 114 of the secondary device 112. The secondary fluid returnpassage 124 extends from a secondary device outlet 116 of the secondarydevice 112 to the fluid return passage 24 downstream of the flowmeterunit 20 and bypass outlet 40.

The secondary flowmeter unit 120 is configured to detect differences inflow between the fluid flowing through the secondary fluid supplypassage 122 and the secondary fluid return passage 124. Specifically, asecondary supply flowmeter 120A is provided between the secondary supplyoutlet 121 and a secondary supply inlet 126 and a secondary returnflowmeter 120B is provided between the secondary return inlet 125 and asecondary return outlet 132. As described in greater detail above, thesecondary flowmeter unit 120 detects leaks from cap loss, hose burst, orinadvertent shutoff and outputs a leak signal upon the detection of aleak similarly to the flowmeter unit 20.

The secondary shutoff valve 128 is positioned on the secondary fluidsupply passage 122 upstream of the secondary flowmeter unit 120.Specifically, the secondary shutoff valve 128 is provided on thesecondary fluid supply passage 122 upstream of the secondary supplyinlet 126. The secondary shutoff valve 128 is switchable between anormally open position and a closed position. In the normally openposition the secondary shutoff valve 128 allows fluid from the secondaryfluid supply passage 122 to flow into the secondary supply inlet 126. Inthe closed position the secondary shutoff valve 128 prevents fluidflowing from the secondary fluid supply passage 122 through thesecondary shutoff valve 128 to the secondary supply inlet 126.

The secondary conduit 146 extends between a secondary drawback opening154 formed on the secondary fluid supply passage 122 and the dualorifice venturi valve 144. The secondary drawback opening 154 isprovided on the secondary fluid supply passage 122 downstream of thesecondary flowmeter unit 120. Specifically, the secondary drawbackopening 154 is positioned on the secondary fluid supply passage 122between the secondary supply outlet 121 and the secondary device inlet114.

The dual orifice venturi valve 144 is positioned on the bypass passage36 between the bypass inlet 38 and the bypass valve 42. The primaryorifice 152A of the dual orifice venturi valve 144 is connected to thedrawback opening 54 by the conduit 46 and the secondary orifice 152B ofthe dual orifice venturi valve 144 is connected to the secondarydrawback opening 154 by the secondary conduit 146.

In some embodiments, the conduit 46 include a junction, similar to thejunction 55 of FIG. 1 to connect the conduit 46 to the drawback opening54 on the fluid supply passage 22 and a drawback opening on the fluidreturn passage 24. In some embodiments, the secondary conduit 146include a junction, similar to the junction 55 of FIG. 1, to connect thesecondary conduit 146 to the secondary drawback opening 154 on thesecondary fluid supply passage 122 and a drawback opening on thesecondary fluid return passage 124. In some other embodiments, both theconduit 46 and the secondary conduit 146 include junctions, similar tothe junction 55 of FIG. 1, to connect the conduit 46 to the drawbackopening 54 on the fluid supply passage 22 and a drawback opening on thefluid return passage 24 to connect the secondary conduit 146 to thesecondary drawback 154 on the secondary fluid supply passage 122 and adrawback opening on the secondary fluid return passage 124

In some embodiments, the conduit 46 includes a check valve positionedbetween the drawback opening 54 and the primary orifice 152A of the dualorifice venturi valve 144. In some embodiments, the secondary conduit146 includes a check valve positioned between the secondary drawbackopening 154 and the secondary orifice 152B of the dual orifice venturivalve 144. In some other embodiments, the conduit 46 includes a checkvalve positioned between the junction and the primary orifice 152A andthe secondary conduit 146 includes a check valve positioned between thejunction and the secondary orifice 152B.

In some embodiments, the venturi vacuum drawback assembly 110 includes aprimary conduit valve 80 and a secondary conduit valve 180. The primaryconduit valve 80 is positioned on the conduit 46 between the drawbackopening 54 and the primary orifice 152A. The primary conduit valve 80 ismovable between a normally closed position, which prevents the flow offluid through the primary conduit valve 80, and an open position, whichpermits the flow of fluid through the primary conduit valve 80. Thesecondary conduit valve 180 is positioned on the secondary conduit 146between the secondary drawback opening 154 and the secondary orifice152B. The secondary conduit valve 180 is movable between a normallyclosed position, which prevents the flow of fluid through the secondaryconduit valve 180, and an open position, which permits the flow of fluidthrough the secondary conduit valve 180.

The electronic control unit 70 is electronically connected to secondaryflowmeter unit 120 similar to the flowmeter unit 20. The electroniccontrol unit 70 is also electronically connected to the shutoff valve28, the secondary shutoff valve 128, the bypass valve 42, the primaryconduit valve 80, and the secondary conduit valve 180. Specifically, theelectronic control unit 70 is configured to control the operation of theshutoff valve 28 between the normally open position and the closedposition. The electronic control unit 70 is further configured tocontrol the operation of the bypass valve 42 between the normally closedposition and the open position. The electronic control unit 70 isconfigured to control the operation of the secondary shutoff valve 128between the normally open position and the closed position. Theelectronic control unit 70 is further configured to control theoperation of the primary conduit valve 80 and the secondary conduitvalve 180 between the normally closed position and the open position. Insome embodiments, the shutoff valve 28, the secondary shutoff valve 128,the bypass valve 42, the primary conduit valve 80, and the secondaryconduit valve 180 are electronically controlled solenoid valves that arecontrolled by the electronic control unit 70.

The detection logic 74A is executed by the processor 72 to detect one ormore signals output from the supply flowmeter 20A, the return flowmeter20B, the secondary supply flowmeter 120A, and the secondary returnflowmeter 120B. For example, the detection logic 74A is configured tocause the processor 72 to determine a presence or absence of a leak inthe coolant delivery system 101, specifically, a leak in at least one ofthe fluid supply passage 22, the device 12, including device inlet 14and the device outlet 16, and the fluid return passage 24 based on thesignals output from at least one of the supply flowmeter 20A and thereturn flowmeter 20B. Specifically, processor 72 determines the presenceor absence of the leak based on output signals from the supply flowmeter20A and the return flowmeter 20B that indicate the flowrates of thefluid supply passage 22 and the fluid return passage 24, respectively.

Further, the detection logic 74A is configured to cause the processor 72to determine a presence or absence of a leak in at least one of thesecondary fluid supply passage 122, the secondary device inlet 114, thesecondary device outlet 116, and the secondary fluid return passage 124based on the signals output from at least one of the secondary supplyflowmeter 120A and the secondary return flowmeter 120B. Specifically,processor 72 determines the presence or absence of the leak based onoutput signals from the secondary supply flowmeter 120A and thesecondary return flowmeter 120B that indicate the flowrates of thesecondary fluid supply passage 122 and the secondary fluid returnpassage 124, respectively.

The control logic 74B is executed by the processor 72 to controloperation of the shutoff valve 28, the secondary shutoff valve 128, andthe bypass valve 42 based on the determination of the presence orabsence of a leak in the coolant delivery system 101. In someembodiments, when the processor 72 has determined the absence of a leak,the control logic 74B maintains the shutoff valve 28 in the normallyopen position, the secondary shutoff valve 128 in the normally openposition, and the bypass valve 42 in the normally closed position.

In order to facilitate a better understanding of the venturi vacuumdrawback assembly 110, a discussion of the operation of the venturivacuum drawback assembly 110 will be provided. During operation in whichthe processor 72 determines the absence of a leak, the coolant deliverysystem 101 operates to deliver fluid from the fluid supply 30 to thedevice 12 through the fluid supply passage 22 and the secondary fluidsupply passage 122 and returns the fluid from the device 12 through thefluid return passage 24 and the secondary fluid return passage 124 tothe recirculation device connected to the fluid return 34. Specifically,during such operation, the shutoff valve 28 is in the normally openposition, the secondary shutoff valve 128 is in the normally openposition, and the bypass valve 42 is in the normally closed position. Asfluid flows through the fluid supply passage 22, the fluid is preventedfrom flowing through the bypass passage 36 as the bypass valve 42 is inthe normally closed position.

During operation in which the processor 72 determines the presence of aleak, the venturi vacuum drawback assembly 110 operates to control theflow of fluid from the device 12. Specifically, upon the processor 72determining the presence of a leak based on the one or more signalsoutput from the supply flowmeter 20A, the return flowmeter 20B, thesecondary supply flowmeter 120A, and the secondary return flowmeter 120Band detected by the detection logic 74A, the control logic 74B isexecuted by the processor 72 to control the shutoff valve 28 from thenormally open position to the closed position, to control the secondaryshutoff valve 128 from the normally open position to the closedposition, and to control the bypass valve 42 from the normally closedposition to the open position.

In some embodiments, the processor 72 executes the control logic 74B toswitch the bypass valve 42 from the normally closed position to the openposition simultaneously with the switching of the shutoff valve 28 andthe secondary shutoff valve 128 from the normally open position to theclosed position. In some embodiments, the processor 72 executes thecontrol logic 74B to switch the bypass valve 42 from the normally closedposition to the open position after an elapse of a preset time periodafter switching of the shutoff valve 28 and the secondary shutoff valve128 from the normally open position to the closed position.

In the closed position, the shutoff valve 28 prevents fluid from flowingfrom the fluid supply 30 through the shutoff valve 28 to the device 12,and the secondary shutoff valve 128 prevents fluid from flowing from thesecondary fluid supply passage 122 through the secondary shutoff valve128 to the device. As fluid is prevented from flowing in the fluidsupply passage 22, downstream of the shutoff valve 28, and fluid isprevented from flowing in the secondary fluid supply passage 122,downstream of the secondary shutoff valve 128, additional fluid isprevented from being discharged through the leak. As the bypass valve 42is in the open position, fluid is permitted to flow through the bypasspassage 36 from the bypass inlet 38 on the fluid supply passage 22upstream of the shutoff valve 28 to the bypass outlet 40 on the fluidreturn passage 24 downstream of the return outlet 32.

As such, fluid flows through the bypass passage 36 including the dualorifice venturi valve 144. Due to the venturi effect of the dual orificeventuri valve 144, a pressure in the dual orifice venturi valve 144upstream of the primary orifice 152A and the secondary orifice 152B ishigher than the pressure downstream of the primary orifice 152A and thesecondary orifice 152B due to the decrease in cross-sectional area atthe constricted portion 60. Accordingly, the fluid remaining in thefluid supply passage 22 downstream of the shutoff valve 28 is at ahigher pressure than the pressure at the primary orifice 152A and thefluid moves from the area of high pressure to the area of low pressureto drain the fluid that remains in the fluid supply passage 22 throughthe venturi valve 44 so as to exit through the fluid return passage 24.Further, the fluid remaining in the secondary fluid supply passage 122downstream of the secondary shutoff valve 128 is at a higher pressurethan the pressure at the secondary orifice 152B and the fluid moves fromthe area of high pressure to the area of low pressure to drain the fluidthat remains in the secondary fluid supply passage 122 through the dualorifice venturi valve 144 so as to exit through the fluid return passage24.

As such, the decrease in pressure creates a vacuum at the primaryorifice 152A which allows the fluid that remains in the fluid supplypassage 22 downstream of the shutoff valve 28 to be drawn throughdrawback opening 54 and into the primary orifice 52 via the conduit 46.Fluid drawn through the primary orifice 52 exits the venturi valve 44via the venturi outlet 50 and enters the fluid return passage 24 via thebypass outlet 40. The decrease in pressure creates a vacuum at thesecondary orifice 152B which allows the fluid that remains in thesecondary fluid supply passage 122 downstream of the secondary shutoffvalve 128 to be drawn through secondary drawback opening 154 and intothe secondary orifice 152B via the secondary conduit 146. Fluid drawnthrough the secondary orifice 152B exits the dual orifice venturi valve144 via the venturi outlet 50 and enters the fluid return passage 24 viathe bypass outlet 40. Therefore, the remaining fluid in the fluid supplypassage 22 downstream of the shutoff valve 28 and the remaining fluid inthe secondary fluid supply passage 122 downstream of the secondaryshutoff valve 128 will not discharge through the leak due to the vacuumeffect of the dual orifice venturi valve 144.

In some embodiments, the dual orifice venturi valve 144 not only drawsback the fluid in the fluid supply passage 22 and the secondary fluidsupply passage 122 but any fluid in the device 12 and/or the fluidreturn passage 24 and the secondary fluid return passage 124 that isdownstream of the leak.

In some embodiments, the detection logic 74A is configured to cause theprocessor 72 to determine a presence or absence of a leak in the fluidsupply passage 22, the fluid return passage 24, and the device 12 basedon the signals output from at least one of the supply flowmeter 20A andthe return flowmeter 20B or a leak in the secondary fluid supply passage122, the device 12 (or the secondary device 112), and the secondaryfluid return passage 124 based on the signals output from at least oneof the secondary supply flowmeter 120A and the secondary returnflowmeter 120B.

In a situation in which the processor 72 determines the presence of aleak in one of the fluid supply passage 22, the fluid return passage 24,the cooling part 18, the device inlet 14, or the device outlet 16, basedon output signals from the supply flowmeter 20A and the return flowmeter20B, and determines the absence of a leak in the secondary fluid supplypassage 122, the secondary fluid return passage 124, the secondarycooling part 118, the secondary device inlet 114, or the secondarydevice outlet 116, based on output signals from the secondary supplyflowmeter 120A and the secondary return flowmeter 120B, the controllogic 74B is executed by the processor 72 to control operation of theshutoff valve 28 to switch from the normally open position to the closedposition, the bypass valve 42 from the normally closed position to theopen position, and the primary conduit valve 80 from the normally closedposition to the open position while maintaining the secondary shutoffvalve 128 in the normally open position and the secondary conduit valve180 in the normally closed position.

Accordingly, fluid flows through the bypass passage 36 including thedual orifice venturi valve 144. Due to the venturi effect of the dualorifice venturi valve 144, a pressure in the dual orifice venturi valve144 upstream of the primary orifice 152A and the secondary orifice 152Bis higher than the pressure downstream of the primary orifice 152A andthe secondary orifice 152B due to the decrease in cross-sectional areaat the constricted portion 160. As the fluid remaining in the fluidsupply passage 22 downstream of the shutoff valve 28 is at a higherpressure than the pressure at the primary orifice 152A and the fluidmoves from the area of high pressure to the area of low pressure todrain the fluid that remains in the fluid supply passage 22 through theventuri valve 44 so as to exit through the fluid return passage 24.Specifically, the fluid remaining in the fluid supply passage 22downstream of the shutoff valve 28 flows from the drawback opening 54through the primary conduit valve 80 in the open position and into theprimary orifice 152A of the dual orifice venturi valve 144.

However, as the secondary conduit valve 180 is in the normally closedposition fluid is prevented from flowing through the secondary conduitvalve 180 into the secondary orifice 152B. Further, as the secondaryshutoff valve 128 is in the normally open position fluid from the fluidsupply 30 passes through the fluid supply passage 22 into the secondaryfluid supply passage 122 and through the secondary shutoff valve 128, inthe normally open position, to the secondary device inlet 114.Accordingly, fluid is prevented from passing through the shutoff valve28 as the presence of a leak was detected by the flowmeter unit 20 andfluid is permitted to pass through the secondary shutoff valve 128 asthe absence of a leak was detected by the secondary flowmeter unit 120.

In a situation in which the processor 72 determines the absence of aleak in one of the fluid supply passage 22, the fluid return passage 24,the cooling part 18, the device inlet 14, or the device outlet 16, basedon output signals from the supply flowmeter 20A and the return flowmeter20B, and determines the presence of a leak in the secondary fluid supplypassage 122, the secondary fluid return passage 124, the secondarycooling part 118, the secondary device inlet 114, or the secondarydevice outlet 116, based on output signals from the secondary supplyflowmeter 120A and the secondary return flowmeter 120B, the controllogic 74B is executed by the processor 72 to control operation of thesecondary shutoff valve 128 to switch from the normally open position tothe closed position, the bypass valve 42 from the normally closedposition to the open position, and the secondary conduit valve 180 fromthe normally closed position to the open position while maintaining theshutoff valve 28 in the normally open position and the primary conduitvalve 80 in the normally closed position.

Accordingly, fluid flows through the bypass passage 36 including thedual orifice venturi valve 144. Due to the venturi effect of the dualorifice venturi valve 144, a pressure in the dual orifice venturi valve144 upstream of the primary orifice 152A and the secondary orifice 152Bis higher than the pressure downstream of the primary orifice 152A andthe secondary orifice 152B due to the decrease in cross-sectional areaat the constricted portion 160. As the fluid remaining in the secondaryfluid supply passage 122 downstream of the secondary shutoff valve 128is at a higher pressure than the pressure at the secondary orifice 152B,the fluid moves from the area of high pressure to the area of lowpressure to drain the fluid that remains in the secondary fluid supplypassage 122 through the dual orifice venturi valve 144 so as to exitthrough the fluid return passage 24. Specifically, the fluid remainingin the secondary fluid supply passage 122 downstream of the secondaryshutoff valve 128 flows from the secondary drawback opening 154 throughthe secondary conduit valve 180 in the open position and into thesecondary orifice 152B of the dual orifice venturi valve 144. The fluidthen exits the bypass passage 36 through the bypass outlet 40 and intothe fluid return passage 24.

However, as the primary conduit valve 80 is in the normally closedposition fluid is prevented from flowing through the primary conduitvalve 80 of the conduit 46 into the primary orifice 152A. Further, asthe shutoff valve 28 is in the normally open position fluid from thefluid supply 30 passes through the fluid supply passage 22 through theshutoff valve 28 in the normally open position to the device inlet 14.Accordingly, fluid is prevented from passing through the secondaryshutoff valve 128 as the presence of a leak was detected by thesecondary flowmeter unit 120 and fluid is permitted to pass through theshutoff valve 28 as the absence of a leak was detected by the flowmeterunit 20.

It is appreciated, that the control logic 74B may include an electroniccontrol start time logic and control stop time logic that when executedby the processor 72 switches the bypass valve 42 from the open positionto the normally closed position after a lapse of a predetermined timefrom the switch of the bypass valve 42 from the normally closed positionto the open position.

In addition, the venturi vacuum drawback assembly 10 and the venturivacuum drawback assembly 110 are optionally used to remove fluidremaining in the fluid supply passage 22 and the secondary fluid supplypassage 122, downstream of the shutoff valve 28 and the secondaryshutoff valve 128, when at least one of the shutoff valve 28 and thesecondary shutoff valve 128 are in the closed position to shut off thesupply of fluid to the device 12 and/or the secondary device 112 duringmaintenance of the device 12 and/or the secondary device 112. Forexample, when replacing cooling parts 18A, such as welding tips of arobotic welding device, the shutoff valve 28 is in the closed positionto shut off the flow of fluid to the device 12 and the bypass valve 42is in the open position to drain the remaining fluid to inhibit theremaining fluid from discharging during replacement of the welding tips18A. Similarly, when replacing cooling parts 18A, such as welding tipsof a robotic welding device, the secondary shutoff valve 128 is in theclosed position to shut off the flow of fluid to the secondary device112 and the bypass valve 42 is in the open position to drain theremaining fluid to inhibit the remaining fluid from discharging duringreplacement of the cooling parts 118A, such as welding tips of asecondary robotic welding device.

However, the use of the venturi vacuum drawback assembly 10, the venturivacuum drawback assembly 10′, and the venturi vacuum drawback assembly110 are not limited thereto. It is appreciated, of course, that theventuri vacuum drawback assembly 10, the venturi vacuum drawbackassembly 10′, and the venturi vacuum drawback assembly 110 areapplicable in various other types of recirculating and non-recirculatingcoolant systems illustratively including internal combustion engines,lasers, battery systems, computer system, and other electronic ormechanical components that requires cooling. Moreover, the venturivacuum drawback assembly 10, the venturi vacuum drawback assembly 10′,and the venturi vacuum drawback assembly 110 are applicable in variousother environments illustratively including, but not limited to, fluidtransfer systems used in manufacturing or agriculture. In such fluidtransfer systems, the venturi vacuum drawback assembly 10, the venturivacuum drawback assembly 10′, and the venturi vacuum drawback assembly110 are utilized to direct the flow of fluid through the venturi effectcaused by the venturi valve 44 and the dual orifice venturi valve 144,respectively.

It is appreciated, that the venturi vacuum drawback assembly 10 of FIG.1 includes the primary conduit valve 80 positioned between the primaryorifice 52 and the junction 55 and that the venturi vacuum drawbackassembly 10′ of FIG. 3 includes the primary conduit valve 80 provided onthe supply conduit 46A between the primary orifice 152A and the drawbackopening 54A and includes the secondary conduit valve 180 provided on thereturn conduit 46B between the secondary orifice 152B and the drawbackopening 54B.

It is appreciated, that the fluid controlled by the venturi vacuumdrawback assembly 10, the venturi vacuum drawback assembly 10′, and theventuri vacuum drawback assembly 110 is a cooling fluid such as acoolant including water based coolants and/or natural or synthetic oilbased coolants.

While particular embodiments and aspects of the present disclosure havebeen illustrated and described herein, various other changes andmodifications can be made without departing from the spirit and scope ofthe disclosure. Moreover, although various aspects have been describedherein, such aspects need not be utilized in combination. It istherefore intended that the appended claims cover all such changes andmodifications that are within the scope of the embodiments shown anddescribed herein.

It is claimed:
 1. A method of controlling a flow of a fluid from adevice, the method comprising: supplying the fluid from a fluid supplyto the device through a fluid supply passage; returning the fluid fromthe device to a fluid return through a fluid return passage; andswitching a shutoff valve positioned on the fluid supply passage from anormally open position to a closed position, in the normally openposition fluid is permitted to flow through the shutoff valve to thedevice, and in the closed position fluid is inhibited from flowingthrough the shutoff valve, and switching a bypass valve positioned on abypass passage from a normally closed position to an open position, thebypass passage includes an inlet and an outlet, the inlet connected tothe fluid supply passage upstream of the shutoff valve, and the outletconnected to the fluid return passage, in the normally closed positionfluid flowing from the fluid supply passage is inhibited from flowingthrough the bypass valve to the fluid return passage, in the openposition fluid flowing from the fluid supply passage is permitted toflow through a venturi valve positioned on the bypass passage betweenthe inlet and the bypass valve; the venturi valve includes a venturiinlet, a venturi outlet, and a primary orifice positioned between theventuri inlet and the venturi outlet, the primary orifice is connectedto a drawback opening on the fluid supply passage by a conduit, thedrawback opening of the fluid supply passage is positioned downstream ofthe shutoff valve; wherein upon switching the shutoff valve from thenormally open position to the normally closed position and switching thebypass valve from the normally closed position to the open position,fluid flowing from the fluid supply passage passes through the bypasspassage to create a vacuum at the primary orifice of the venturi valvethat draws fluid remaining in the fluid supply passage downstream of theshutoff valve through the drawback opening in the fluid supply passageand the conduit such that the fluid exits the venturi outlet into thefluid return passage through the outlet of the bypass passage.
 2. Themethod of claim 1, wherein the venturi valve includes a constrictedportion at which the primary orifice is located, the venturi inlet hasan inlet orifice at the constricted portion, the venturi outlet has anoutlet orifice at the constricted portion, wherein an area of the outletorifice is equal to or less than a sum of an area of the primary orificeand an area of the inlet orifice.
 3. The method of claim 1 furthercomprising: detecting a leak in at least one of the fluid supply passageand the fluid return passage, wherein upon detection of the leak,switching the shutoff valve from the normally open position to closedposition and switching the bypass valve from the normally closedposition to open position.
 4. The method of claim 3, wherein the leak isdetected by a flowmeter unit positioned on at least one of the fluidsupply passage and the fluid return passage, the flowmeter unit isconfigured to control the shutoff valve to switch from the normally openposition to closed position upon detection of the leak by the flowmeterunit and to control the bypass valve to switch from the normally closedposition to the open position upon detection of the leak by theflowmeter unit.
 5. The method of claim 4, wherein the venturi valveincludes a constricted portion at which the primary orifice is located,the venturi inlet has an inlet orifice at the constricted portion, theventuri outlet has an outlet orifice at the constricted portion, whereinan area of the outlet orifice is equal to or less than a sum of an areaof the primary orifice and an area of the inlet orifice.
 6. The methodof claim 5, wherein the flowmeter unit is configured to control thebypass valve to switch from the normally closed position to the openposition simultaneously with the control of the shutoff valve to switchfrom the normally open position to the closed position.
 7. The method ofclaim 5, wherein the flowmeter unit is configured to control the bypassvalve to switch from the normally closed position to the open positionafter an elapse of a preset time period after the control of the shutoffvalve to switch from the normally open position to the closed position.8. A method of controlling a flow of a fluid from a device, the methodcomprising: supplying the fluid from a fluid supply to the devicethrough a fluid supply passage; returning the fluid from the device to afluid return through a fluid return passage; and switching a shutoffvalve positioned on the fluid supply passage from a normally openposition to a closed position, in the normally open position fluid ispermitted to flow through the shutoff valve to the device, and in theclosed position fluid is inhibited from flowing through the shutoffvalve, and switching a bypass valve positioned on a bypass passage froma normally closed position to an open position, the bypass passageincludes an inlet and an outlet, the inlet connected to the fluid supplypassage upstream of the shutoff valve, and the outlet connected to thefluid return passage, in the normally closed position fluid flowing fromthe fluid supply passage is inhibited from flowing through the bypassvalve to the fluid return passage, in the open position fluid flowingfrom the fluid supply passage is permitted to flow through a venturivalve positioned on the bypass passage between the inlet and the bypassvalve; the venturi valve includes a venturi inlet, a venturi outlet, aprimary orifice positioned between the venturi inlet and the venturioutlet, and a secondary orifice positioned between the venturi inlet andthe venturi outlet, the primary orifice is connected to a primarydrawback opening on the fluid supply passage by a primary conduit, theprimary drawback opening is positioned on the fluid supply passagedownstream of the shutoff valve, the secondary orifice is connected to asecondary drawback opening on the fluid return passage by a secondaryconduit, the secondary drawback opening is positioned on the fluidreturn passage between the device and the outlet of the bypass passage;wherein upon switching the shutoff valve from the normally open positionto the normally closed position and switching the bypass valve from thenormally closed position to the open position, fluid flowing from thefluid supply passage passes through the bypass passage to create avacuum at the primary orifice of the venturi valve that draws fluidremaining in the fluid supply passage downstream of the shutoff valvethrough the primary drawback opening on the fluid supply passage and theprimary conduit such that the fluid exits the venturi outlet into thefluid return passage through the outlet of the bypass passage, and fluidflowing from the fluid supply passage passes through the bypass passageto create a vacuum at the secondary orifice of the venturi valve thatdraws fluid remaining in the fluid return passage between the device andthe outlet of the bypass passage through the secondary drawback openingon the fluid return passage and the secondary conduit such that thefluid exits the venturi outlet into the fluid return passage through theoutlet of the bypass passage.
 9. The method of claim 8, wherein theventuri valve includes a constricted portion at which the primaryorifice and the secondary orifice are located, the venturi inlet has aninlet orifice at the constricted portion, the venturi outlet has anoutlet orifice at the constricted portion, wherein an area of the outletorifice is equal to or less than a sum of an area of the primaryorifice, an area of the secondary orifice, and an area of the inletorifice.
 10. The method of claim 8 further comprising: detecting a leakin at least one of the fluid supply passage and the fluid returnpassage, wherein upon detection of the leak, switching the shutoff valvefrom the normally open position to the closed position and switching thebypass valve from the normally closed position to open position.
 11. Themethod of claim 10, wherein the leak is detected by a flowmeter unitpositioned on at least one of the fluid supply passage and the fluidreturn passage, the flowmeter unit is configured to control the shutoffvalve to switch from the normally open position to closed position upondetection of the leak by the flowmeter unit and to control the bypassvalve to switch from the normally closed position to the open positionupon detection of the leak by the flowmeter unit.
 12. The method ofclaim 11, wherein the venturi valve includes a constricted portion atwhich the primary orifice is located, the venturi inlet has an inletorifice at the constricted portion, the venturi outlet has an outletorifice at the constricted portion, wherein an area of the outletorifice is equal to or less than a sum of an area of the primary orificeand an area of the inlet orifice.
 13. The method of claim 12, whereinthe flowmeter unit is configured to control the bypass valve to switchfrom the normally closed position to the open position simultaneouslywith the control of the shutoff valve to switch from the normally openposition to the closed position.
 14. The method of claim 12, wherein theflowmeter unit is configured to control the bypass valve to switch fromthe normally closed position to the open position after an elapse of apreset time period after the control of the shutoff valve to switch fromthe normally open position to the closed position.
 15. A method ofcontrolling a flow of a fluid from a device, the method comprising:supplying the fluid from a fluid supply to the device through a primaryfluid supply passage and a secondary fluid supply passage; returning thefluid from the device to a fluid return through a primary fluid returnpassage and a secondary fluid return passage; and switching a primaryshutoff valve positioned on the primary fluid supply passage from anormally open position to a closed position, in the normally openposition fluid is permitted to flow through the primary shutoff valve tothe device, and in the closed position fluid is inhibited from flowingthrough the primary shutoff valve, and switching a bypass valvepositioned on a bypass passage from a normally closed position to anopen position, the bypass passage includes an inlet and an outlet, theinlet connected to the primary fluid supply passage upstream of theprimary shutoff valve, and the outlet connected to the primary fluidreturn passage, in the normally closed position fluid flowing from theprimary fluid supply passage is inhibited from flowing through thebypass valve to the primary fluid return passage, in the open positionfluid flowing from the primary fluid supply passage is permitted to flowthrough a venturi valve positioned on the bypass passage between theinlet and the bypass valve, the venturi valve includes a venturi inlet,a venturi outlet, a primary orifice positioned between the venturi inletand the venturi outlet, and a secondary orifice positioned between theventuri inlet and the venturi outlet, the primary orifice is connectedto a primary drawback opening on the primary fluid supply passage by aprimary conduit, the primary drawback opening is positioned on theprimary fluid supply passage downstream of the shutoff valve, thesecondary orifice is connected to a secondary drawback opening on thesecondary fluid return passage by a secondary conduit, the secondarydrawback opening is positioned on the secondary fluid return passagebetween the device and the outlet of the bypass passage, wherein uponswitching the primary shutoff valve from the normally open position tothe normally closed position and switching the bypass valve from thenormally closed position to the open position, fluid flowing from theprimary fluid supply passage passes through the bypass passage to createa vacuum at the primary orifice of the venturi valve that draws fluidremaining in the primary fluid supply passage downstream of the primaryshutoff valve through the primary drawback opening on the primary fluidsupply passage and the primary conduit such that the fluid exits theventuri outlet into the primary fluid return passage through the outletof the bypass passage.
 16. The method of claim 15, wherein the venturivalve includes a constricted portion at which the primary orifice andthe secondary orifice are located the venturi inlet has an inlet orificeat the constricted portion, the venturi outlet has an outlet orifice atthe constricted portion, wherein an area of the outlet orifice is equalto or less than a sum of an area of the primary orifice, an area of thesecondary orifice, and an area of the inlet orifice.
 17. The method ofclaim 15 further comprising: detecting a leak, by a flowmeter unit, inat least one of the primary fluid supply passage and the primary fluidreturn passage and in at least one of the secondary fluid supply passageand the secondary fluid return passage, the flowmeter unit positioned ison at least one of the primary fluid supply passage and the primaryfluid return passage, and on at least one of the secondary fluid supplypassage and the secondary fluid return passage; and upon detecting theleak in at least one of the primary fluid supply passage and the primaryfluid return passage, the flowmeter unit is configured to control theprimary shutoff valve to switch from the normally open position to theclosed position and to control the bypass valve to switch from thenormally closed position to the open position.
 18. The method of claim17 further comprising: upon detecting the leak in at least one of theprimary fluid supply passage and the primary fluid return passage,switching a primary conduit valve positioned on the primary conduit froma normally closed position to an open position, in the normally closedposition fluid is inhibited from flowing through the primary conduitvalve from the primary drawback opening to the primary orifice, and inthe open position fluid is permitted to flowing through the primaryconduit valve from the primary drawback opening to the primary orifice.19. The method of claim 16 further comprising: detecting a leak, by aflowmeter unit, in at least one of the primary fluid supply passage andthe primary fluid return passage and in at least one of the secondaryfluid supply passage and the secondary fluid return passage, theflowmeter unit positioned is on at least one of the primary fluid supplypassage and the primary fluid return passage, and on at least one of thesecondary fluid supply passage and the secondary fluid return passage;and upon detecting the leak in at least one of the secondary fluidsupply passage and the secondary fluid return passage, switching asecondary shutoff valve positioned on the secondary fluid supply passagefrom a normally open position to a closed position, in the normally openposition fluid is permitted to flow through the secondary shutoff valveto the device, and in the closed position fluid is inhibited fromflowing through the secondary shutoff valve, and switching the bypassvalve from the normally closed position to the open position, whereinupon switching the secondary shutoff valve from the normally openposition to the normally closed position and switching the bypass valvefrom the normally closed position to the open position, fluid flowingfrom the primary fluid supply passage passes through the bypass passageto create a vacuum at the secondary orifice of the venturi valve thatdraws fluid remaining in the secondary fluid supply passage downstreamof the secondary shutoff valve through the secondary drawback opening onthe secondary fluid supply passage and the secondary conduit such thatthe fluid exits the venturi outlet into the primary fluid return passagethrough the outlet of the bypass passage.
 20. The method of claim 19further comprising: upon detecting the leak in at least one of thesecondary fluid supply passage and the secondary fluid return passage,switching a secondary conduit valve positioned on the secondary conduitfrom a normally closed position to an open position, in the normallyclosed position fluid is inhibited from flowing through the secondaryconduit valve from the secondary drawback opening to the secondaryorifice, and in the open position fluid is permitted to flowing throughthe secondary conduit valve from the secondary drawback opening to thesecondary orifice.